Looking to replace diff bushes, feels really clunky in the rear end when I hit high revs and shift too quickly. I've read mixed reports of the nylon bushes and I've also read some good reviews of the "super pro" diff bushes, would like to know where to purchase as well. Also how hard are they to replace (my brothers is a heavy diesel mechanic), is it hard to stuff it up? And last of all, am I doing damage to my car by letting this go on? Thanks for reading!